Baseball America's Top 10 Prospects lists are based on projections of a player's long-term worth after discussions with scouting and player-development personnel. All players who haven't exceeded the major league rookie standards of 130 at-bats or 50 innings pitched (without regard to service time) are eligible.

Though the Mariners finished last in the American League West for the third straight season, they continue to make marginal improvements under general manager Jack Zduriencik and to rebuild patiently after former GM Bill Bavasi left the team with bad contracts and a gutted farm system.

While the past few years have been bleak, Seattle's future appears brighter. It has a young core at the big league level, starting with Felix Hernandez, who threw the first perfect game in franchise history on Aug. 15 and continues to rank among the best pitchers in the game. Kyle Seager broke out and led the team with 20 home runs. Rookie Jesus Montero, acquired from the Yankees along with Hector Noesi for Michael Pineda and righthander Jose Campos in the offseason, became the youngest player (age 22) to hit 15 homers for the Mariners since Alex Rodriguez in 1998.

Despite the positives, the Mariners expected more from the likes of Dustin Ackley and Justin Smoak. Drafted No. 2 overall behind Stephen Strasburg in 2009, Ackley batted just .226/.294/.328. Smoak, the key player in the Cliff Lee trade with the Rangers in 2010, was just as bad for most of the season but provided some hope by hitting .338 with five homers in September.

After finishing last in the AL in scoring for the fourth straight year, Seattle announced it would move the fences in at Safeco Field for 2013.

Hope is on the horizon, as the Mariners have one of the best farm systems in baseball. Seattle has top-tier talent, most notably an outstanding group of pitching prospects, along with depth and balance. Scouting director Tom McNamara and his staff have restocked the system in a short time, identifying quality players with their top picks—Ackley, righthander Taijuan Walker, lefty Danny Hultzen and catcher Mike Zunino—and finding value in the later rounds.

Jackson led the Double-A Southern League with a 3.37 ERA with a staff that featured all of the organization's top pitching prospects at some point. Carter Capps and Stephen Pryor contributed to the big league bullpen by the end of the season, while starters Walker, Hultzen, James Paxton and Brandon Maurer could arrive in 2013 after some Triple-A time.

The Mariners also have a few hitters on the way. Zunino had a stellar pro debut and reached Double-A after signing for $4 million as the No. 3 overall pick in the 2012 draft. Seattle has a number of middle-infield options in the upper minors as well, highlighted by Nick Franklin, Stefen Romero and Brad Miller.

After the season ended, the Mariners significantly revamped their international scouting department. They fired Latin America coordinator Patrick Guerrero, a move that prompted international scouting director Bob Engle to announce he wouldn't return when his contract expired. Both Engle and Guerrero joined the Dodgers.

Engle, who had been with Seattle since January 2000, oversaw the signings of Hernandez, Pineda, Shin-Soo Choo, Asdrubal Cabrera and several other big leaguers. He previously had been the scouting director for the Blue Jays, with whom he was involved in drafting Cy Young Award winners Chris Carpenter, Roy Halladay and Pat Hentgen.